Electrostatic discharge research at the University of Ottawa

An experimental system developed at the University of Ottawa to measure the fields radiated by the electrostatic discharge (ESD) spark is described. Its key features are a Tektronix 7912HB transient digitizer with 750 MHz single-shot bandwidth for voltage measurement, and a broadband time-domain electric-field sensor. The system is modeled in four parts: (1) a source of charge, (2) a spark gap, (3) a target, and (4) a voltage-transient digitizer. For a source, P. Richman's (1985) DUAL-RLC human body model was used. A zero-resistance spark gap is assumed. The target is essentially a current-to-voltage converter-typically, a distributed 2 Omega resistor. These were combined with a simple one-pole model of an oscilloscope to build a SPICE simulation model of the system. The body capacitance was set to an initial condition of 2 kV, and a transient analysis was performed to simulate the image, i.e., the displayed waveform, on the oscilloscope. A bandwidth of 750 MHz was seen to be adequate to observe both the risetime and the peak of the ESD current, given the above model parameters.<>